This program is a renewal of CA34847. A multidisciplinary research team from three participating institutions will carry out cost efficient population-based cancer prevention research with the primary goal of lowering community measures of cancer incidence and mortality. The proposed research program builds directly on research projects during years 01-05. lt is based in the research populations and uses the research resources established by the year 01-05 investigators. The shared resources will be used to capitalize on multi-project experience and data to make advances in the strategies, methods and rigor of cancer prevention research. The program's theme is primary prevention of cancer morbidity and mortality. It emphasizes two methodologies: dietary intervention and community intervention, in recognition that successful primary prevention must be population-based and that tobacco and dietary interventions hold out most promise for impact on public health measures. It includes three chemoprevention projects. The first will make long-term assessments of safety and compliance of the retinol and beta-carotene intervention proposed for use in a full scale multicenter trial. The second project is the start-up phase of that trial. The third chemoprevention trial is the completion of a trial with folic acid to prevent cervical cancer. There are three studies of dietary modification. The first is a trial of intervention diffusion and primary prevention, the second is a trial of a mass approach to dietary intervention and the third is a study of a relationship between diet and cancer mortality. The program has two tobacco related projects. The first is concerned with the prevention of smokeless tobacco use in the school population, the second with smoking cessation in an entire worksite population. There are two community-based projects to increase the use of mammography and one project to develop community intervention strategies and methods. Two population based shared resources are: an enrolled population of 300,000; and cancer and cancer risk behavior surveillance of the population of Western Washington. The other four resources support social research and survey activities, nutritional epidemiological activities, cost analysis activities and measurements of behavior. All the projects have been conceptualized and developed as multidisciplinary research projects and all have been subjected to and passed the program review procedures.